A diffraction pattern is obtained by using a beam of red light. If the red light is replaced by the blue light
A diffraction pattern is obtained by using a beam of red light. If the red light is replaced by the blue light
bands will be narrower
bands become broader
no change in the width of the bands takes place
bands disappear
Solution
The width of the fringe in diffraction, $\beta=\frac{D \lambda}{d}$ Hence, when the red light is replaced by blue light, the wavelength decreases which means that the fringe width decreases and band will be narrower.